A coaxial connector used as a test port of a test system (e.g., a vector network analyzer) requires calibration to impart accuracy to the test system. Calibrating test ports typically includes measuring precision coaxial standards having parameters incorporated into the test system. One of the requirements for calibrating test ports is a through measurement of a coaxial standard or alternatively, connection of two test ports. The test ports must either mate with each other or with opposite ends of the coaxial standard. If the test ports are mated without a coaxial standard, then one test port must be a male connector and the other test port must be a female connector. If the test ports are mated with a coaxial standard, the test ports must mate with opposite ends of the coaxial standard. Where the coaxial standard includes opposite ends that are male connectors, the test ports must each be female connectors.
Often, a device under test (DUT) does not have connectors of the same sex as the calibration standard (for instance, the DUT connectors are often female/female and will not mate with the test ports described above). Unfortunately, the use of additional intermediary adapters to change the sex of one or more of the test ports to accommodate the DUT can seriously degrade calibration. It can therefore be desirable to have the ability to change the sex of the test port without degrading calibration.
One method of changing the sex of a test port is described in U.S. Pat. No. 4,891,015 entitled “Universal Connector with Interchangeable Male and Female Sleeves for Use in Network Analyzers and Microwave Devices,” issued to Oldfield. The design disclosed in Oldfield '015 can be non-optimal for very high frequency coaxial connectors, such as 1.85 mm and 1 mm connectors. These connectors are very small and pose particular problems. One problem is that calibration components used for the smaller connectors are often line-reflect-line (LRL) components. LRL components are coaxial through-lines that have no center conductor support. Where the length of the lines is long, as is required for lower frequency calibration, the second connection is difficult to consummate because the center conductor is often not centered and will not mate with the test port. Also, the interface between the test port and the LRL can be hidden from view during mating, due to overlapping connection parts of the coaxial connectors. Also problematic for LRL components is installation of a male pin for changing the sex of the connector from female to male. The small diameter of the male pin—the 1 mm connector pin is less than 0.010 inches in diameter—can make installation difficult and less convenient.